1. Field of the Invention
The present invention relates to a reciprocating type electric shaver provided with a trimmer blade that is substantially reverse L-shaped in cross section.
2. Description of the Related Art
A typical reciprocating type electric shaver includes a finishing blade that cuts by causing its movable inner cutter to make sliding contact with the inner surface of its stationary or immovable outer cutter that is curved in an arch shape; and hair, for instance, whiskers, that enters hair introduction holes of the outer cutter is cut by the reciprocating inner cutter.
Reciprocating type electric shavers that have trimmer blades in addition to the above-described finishing blade are also known.
The finishing blade has hair introduction holes in a form of a plurality of small holes in the outer cutter. Accordingly, the problem is that though relatively straight hair can enter into the hair introduction holes easily and is cut, curved unruly hair has difficulty to go into the hair introduction holes.
On the other hand, the trimmer blade is to introduce unruly hair thereinto and cut it smoothly. Accordingly, the hair introduction holes of the outer cutter of the trimmer blade are typically in a slit shape.
More specifically, the trimmer blade is in a shape of a reversed L shape (or the cross section is substantially a reverse L shape), and the outer cutter thereof has a horizontal bent part in which slits are formed so that they open toward the open end side of the horizontal bent part, and the comb-shaped portion remaining between the slits scrapes up the hair and guides it into the slits for cutting. Thus, the trimmer blade can cut curved unruly hair easily and well.
Japanese Patent Application Laid-Open (Kokai) No. 2000-84270 shows a reciprocating type electric shaver that includes an arch-shaped finishing blade (indicated by reference numeral 5 in FIG. 1 of this related art), a rectangular coarse shaving slit blade (reference numeral 6 in FIG. 1 of this related art), and a trimmer blade that is reverse L-shaped in cross section (reference numeral 7 in FIG. 1 of this related art); and these blades are provided in parallel.
In the trimmer blade (7) of this related art, hair enters the slits (slit blade 75) that open on the leading end (open end) side of the outer cutter (upper stationary outer cutter 71, see FIGS. 6-9 of this related) and is cut by the inner cutter (lower moving cutter 72). This related art further shows a slit holes (76) that projects upward in the bent part of the outer cutter; however, this slit holes (76) are those that scrape up curved hair guided to the adjacent finishing blade (5), and it is not a cutter for cutting hair (see paragraphs 0021 and 0022 of this related art).
FIG. 6 shows another type of one of known reciprocating type electric shavers. FIG. 7 shows the trimmer blade of this shaver, and FIG. 8 is a disassembled perspective view thereof. Also, FIGS. 9A through 9C show the stationary outer cutter of the trimmer blade.
In FIG. 6, the reference numeral 10 is a shaver main body, and a shaver head 12 is detachably attached to the upper part of the shaver main body 10. The shaver main body 10 includes an electric motor and a rechargeable battery (both not shown in the drawings). A pair of finishing blades 14 are provided in parallel in the shaver head 12, with a trimmer blade 16 in between.
Each of the finishing blades 14 has a stationary outer cutter comprising a thin metal plate that is curved in an arch shape and a movable inner cutter (not shown in the drawings) that makes reciprocating motion inside the stationary outer cutter. A plurality of small holes (hair introduction holes) open in the outer cutter. The inner cutter has a plurality of arch-shaped cutter blades aligned orthogonal to the reciprocating direction or in the lengthwise direction, and hair that enters the small holes of the outer cutter is cut by the reciprocating inner cutter.
The trimmer blade 16 is a combination of, as seen from FIG. 8, a stationary or immovable outer cutter 18 (called “outer cutter”), which is substantially reverse L-shaped in cross section, and a movable inner cutter 20 (called “inner cutter”), which makes reciprocating motion inside or underneath the stationary outer cutter 18. The outer cutter 18 has a flat standing wall part 22 and a horizontal bent part 24 that is horizontally bent at the upper end of the flat standing wall part 22. Formed in the horizontal bent part 24 of the inner cutter 20 are a plurality of slits 28 that open toward its open end 26 side. As is clear from FIG. 9A, these slits 28 are closed on the side opposite from the open end 26; in other words, the slits 28 are closed on the bent corner 30 side (which is on the right side of the horizontal bent part 24 in FIGS. 9A and 9C). These slits 28 are orthogonal to the longitudinal direction of the standing wall part 22, that is, orthogonal to the reciprocating direction (shown by arrow R in FIG. 8) of the inner cutter 20.
As seen from FIG. 9C, the inner cutter 20 is substantially a reverse L shape, and it includes a support part 32 that extends downward and a horizontal bent part 34 that is horizontally bent at the upper end of the support part 32. Formed in the horizontal bent part 34 are a plurality of slits 36 that open toward its open end side or left side in FIG. 9C. Accordingly, the horizontal bent part 24 of the outer cutter 18 and the horizontal bent part 34 of the inner cutter 20 have a substantially comb shape due to the portions remaining between the slits 28 and 36. As shown in FIG. 9C, the open end 26 of the horizontal bent part 24 of the outer cutter 18 bends slightly downward in a substantially hook shape, so that the downwardly bent portion conceals the open end of the horizontal bent part 34 of the inner cutter 20.
The outer cutter 20 and the inner cutter 18 are combined and integrated as shown in FIG. 7. As seen from FIG. 8, a sliding plate 38 is fixed to the support part 32 of the inner cutter 20, and a pair of flat springs 40 that extend in a wing-form are fixed to both side edges of the sliding plate 38. The outer cutter 18 is inserted into and held by a pair of resin end members 42 at both ends.
The inner cutter 20 is provided inside the outer cutter 18; and when the inner cutter 20 is thus installed inside the outer cutter 18, the tip ends of the flat springs 40 held on the sliding plate 38 touch from above the horizontal surfaces 44 of the end members 42 that hold the outer cutter 18. Accordingly, the inner cutter 20 is pushed upward by the flat springs 40 and is elastically compressed at the outer cutter 18 from below. Under this state, a presser plate 46 is attached to the end member 42 from the side opposite the standing wall part 22 of the outer cutter 18. The presser plate 46 is fixed to the end members 42 by pressing a left/right pair of catches 48 into engagement openings 50 in the end member 42.
Because of the structure described above, the inner cutter 20 and sliding plate 38 are sandwiched between the standing wall part 22 of the outer cutter 18 and the presser plate 46 and held so that they can reciprocate freely sideways. The inner cutter 20 is pushed upward by the flat springs 40, and the upper surface of the horizontal bent part 34 of the inner cutter 20 makes elastic contact with the lower surface of the horizontal bent part 24 of the outer cutter 18. A pin (not shown in the drawings) that is reciprocatingly driven by the motor of the shaver main body 10 engages a downwardly-opened groove 52 of the sliding plate 38 and reciprocates the inner cutter 20. Hair entered the slits 28 of the outer cutter 18 is cut by the reciprocating inner cutter 20.
In this shaver, all of the slits 28 of the outer cutter 18 open toward the open end 26 side of the horizontal bent part 24. Accordingly, when the shaver head 12 is moved down to the left in FIG. 6 (or in the direction of arrow O), that is, in the direction in which the slits 28 open, hair enters the slits 28 in good order and as a result is cut. However, when the head 12 is moved to the opposite side (or in the direction opposite to the direction O), then hair cannot be introduced into the slits 28 smoothly. The resulting problem is that unruly hair cannot be cut adequately.
A concept that is to solve this problem is to have the slits 28 open not only on the open end side but also on the bent corner 30 side that is the opposite from the open end 26 side. However, if the slits 28 open on both open and bent corner sides, then a problem arises that the comb-like portion remaining between the slits 28 loses its strength.